Dashcam footage of Sandra Bland’s arrest during a traffic stop before her death in police custody. Note: this edited video contains some cuts that were in the original supplied footage. Link to video.

Texas officials have denied that video of a violent traffic stop that led to Sandra Bland being taken to the jail where she was later found dead had been doctored.

The Texas department of public safety released the dashcam footage from trooper Brian Encinia’s car on Tuesday evening, in response to intense public scrutiny of the last days of the 28-year-old black woman’s life. Police have said Bland was found hanged in her cell on 13 July, three days after she was arrested for assault on a public servant in Prairie View, near Houston.

The dashcam footage shows an initially routine traffic stop for failing to signal a lane change turn into an aggressive encounter as the trooper, apparently furious that Bland refused to stop smoking, repeatedly orders her to get out of her car, yells at her, says he will “yank” her out then draws his Taser and shouts: “I will light you up.”

Once out and restrained, Bland screams, sobs and complains off-camera that she is in pain and has been “slammed” to the ground.

But the 52-minute video quickly attracted scrutiny on social media because at various points following Bland’s arrest the images briefly loop and jump, with cars disappearing and a man repeatedly seen getting out of a tow truck. The audio does not appear to be disrupted.

Ava DuVernay, the director of Selma, posted on Twitter: “I edit footage for a living. But anyone can see that this official video has been cut.”

A lawyer representing the family of Sandra Bland says her death was totally avoidable.

On Wednesday afternoon, the department issued a revised version of the video which appears to correct the loops and jumps and is about three minutes shorter. In a statement, a Texas DPS spokesman denied that Tuesday’s video had been edited.

“Yesterday’s video was not edited. The entire video was uploaded Tuesday to include the audio and video of the conversation the trooper had by telephone with his sergeant, which occurred after the arrest. Some of the video was affected in the upload. That technical issue has now been resolved.”

Earlier in the day, a Texas DPS spokesman said the irregularities were the result of a technical glitch. “The video has not been edited. To eliminate any concerns as to the efficacy of the video DPS previously requested the FBI examine the dash cam and jail video to ensure the integrity of the video,” he said.

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The discrepancies have fuelled already widespread scepticism about how committed investigators are to transparency in a county with a long history of racism, and doubts over the official version of events, which is that Bland hanged herself with a plastic garbage bag. Her family have dismissed the idea that she would kill herself as “unfathomable”, especially since she had just moved to Texas from Chicago to start a new job.

On Monday, Waller county officials released three hours of footage from the jail, but the inside of Bland’s cell is not visible and there are gaps in the images, which they said was because the camera is motion-activated and does not record when the hallway is still.

Encinia is on desk duty after the Texas DPS said that he violated agency protocols during the stop.

Brian Encinia, 30, joined the Texas Department of Safety in February 2014 and is listed as Hispanic on Texas voter registration records.

Encinia had worked as a supervisor at an ice cream manufacturer in his hometown of Brenham, Texas, from 2008 and volunteered at the city’s fire department from November 2009.

“We never had any issues with him. He was respected by everybody and during his last year here, he was was even made one of our officers in the department,” Baker said.

Asked what he thought of Encinia’s conduct during Bland’s arrest, Baker, who had not watched full video, said: “That’s not the Brian we knew.”

Another trooper was involved in Bland’s arrest, but Elton Mathis, the Waller district attorney, said that her dashcam video was unavailable, apparently because the device’s memory was full.

The footage released on Tuesday shows Bland holding her phone as she exits her vehicle before Encinia tells her to put it away. Another video of part of Bland’s arrest, shot by a passerby, emerged last week. “You need to leave,” Encinia tells the witness. “Thank you for recording!” Bland says.